Millions of shredded ex-East German secret police papers could be pieced together by new computer technology.

The documents - destroyed in 1989 - are thought to be records on paid up but unofficial employees and spies.

Developers IPK and Lufthansa say the technology could reconstruct the papers within five years at about 10m euros ($11m) per year.

Funding for the project must first be approved by the German parliament before it can continue.

Skeletons

The documents mostly relate to the period between 1970 to the end of the 1980s, officials say.

About 500,000 pages have already been stuck together by hand.

But this is only 250 sacks worth of the total 16,000 sacks of shredded material being held in the archive.

Stasi files were 'panic' shredded when communism collapsed

The existing 15-person manual reconstruction team would have taken another 400 years to finish the process, but the computer system is expected do it in less than five years.

The new system would scan several pieces of shredded documents simultaneously, looking for "descriptive characteristics" such as paper colour, texture handwriting or typeset, explained Ottmar Buennemeyer, a spokesman for IPK said.

"Luckily, the Stasi tore the files directly into sacks so we can almost be sure all the pieces of the documents are in the
same sack," he added.

Special software would then match up pieces based on their similarities and paste them together to recreate the original
document.

Collaboration

Bertram Nickolay from the Fraunhofer Institute for Production Systems and Design Technology had already been using the process to piece together shredded files from Nazi concentration camps.

"Seven years ago we learned that the archive was doing this by hand so we began working with Lufthansa Systems to adapt its existing analysis systems to scan and sort the Stasi papers," he said.

In September, a German court lifted a ban preventing the release of 2,500 pages of Stasi files collected on the country's former chancellor, Helmut Kohl.

Laws over the files grant researchers and journalists access, so long as they information they hold was not obtained through measures that violate human rights, including eavesdropping and interception of letters.